A novel modular technique for die-level liquid cooling

ABSTRACT

An integrated circuit assembly including a first die including a device side and a backside opposite the device side; and a second die including a plurality of fluidly accessible channels therein, wherein the second die is coupled to a backside of the first die. A method of fabricating an integrated circuit assembly including coupling a first die to a second die, wherein the first die includes a device side and an opposite backside, wherein the device side includes a plurality of integrated circuits and wherein the second die includes a plurality of fluidly accessible channels therein.

FIELD

Thermal management for integrated circuit devices.

BACKGROUND

Decreasing feature sizes and increasing package densities are makingthermal issues important in integrated circuit related products,particularly high power products such as server products. The totalthermal design power is increasing with respect to generation whichdemands that cross-plane heat removal be improved. Still further, theemergence of multi-chip packages (MCPs) in, for example, high-powerservers where, for example, multi-chip dynamic random access memory(MC-DRAM) stacked packages currently generate approximately nine wattsto 10 watts of power and come coated with die backside film polymericlayers that present a high thermal resistance that is difficult tocompensate for with traditional air cooling.

Many high-power central processing unit (CPU) products use an integratedheat spreader (IHS) as a lid over the die (e.g., a silicon die or dice).Onto this lid mounts a thermal solution, such as a passive heat sink, aheat sink/fan combination or liquid cooling solution. Limitations ofthese configurations include a relatively large stack-up height andmultiple thermal interfaces where thermal interface material (TIM) mustbe applied. Thermal performance of TIM materials have been optimized yeta need still remains to improve the thermal management of high-powermicroprocessors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional and schematic side view of an embodimentof an integrated circuit chip assembly that includes a thermal solution.

FIG. 2A shows a top perspective view of a die including channelsoperable to be attached to a die having active devices and circuitry aspart of a thermal solution.

FIG. 2B shows a top perspective view of another embodiment of a dieincluding channels therein operable to be attached to a die havingactive devices and circuitry offering a thermal solution.

FIG. 3 shows a top perspective view of the die of FIG. 2A following theformation of a thermally conductive material.

FIG. 4 shows a top perspective view of an embodiment of a die includingactive devices and circuits processed to receive the die of FIG. 3 bythe formation of a conductive material on a backside of the die.

FIG. 5 shows the connecting of the die of FIG. 3 to the die of FIG. 4.

FIG. 6 shows the assembly including the connected dice of FIG. 3 andFIG. 4.

FIG. 7 provides a flow chart of a method of forming an assemblyincluding a die with channels therein connected to a die with activedevices and circuits.

FIG. 8 shows another embodiment of an assembly including a die includingchannels connected to a die with active devices and circuitry formedtherein for a fluid cooling solution.

FIG. 9 shows a cross-sectional side view of another embodiment of anassembly offering a thermal solution.

FIG. 10 shows a cross-sectional side view of another embodiment of anassembly offering a thermal solution.

FIG. 11 illustrates an embodiment of a computing device.

DETAILED DESCRIPTION

FIG. 1 shows a cross-sectional and schematic side view of an embodimentof an apparatus that includes a thermal solution. FIG. 1 shows die 105that is, for example, a logic die (e.g., a processor) formed from asemiconductor material platform connected to substrate 130 such as apackage substrate. In this embodiment, die 105 has device side 106including a number of contacts to transistor devices and circuits in adevice layer and backside 107 opposite device side 106. Device side 106is connected to substrate 115 (e.g., a package substrate) through, forexample, solder connections 125.

Connected to backside 107 of die 105 is die 120 or secondary die 120. Inone embodiment, die 120 is a semiconductor material (e.g., silicon) thatis not an active die (e.g., does not include any active devices formedin a device layer, where an active device is a device capable ofcontrolling electrical current by means of an electrical signal. Die 120includes a body and a number of laterally disposed channels formed inthe body of the die. In this embodiment, the laterally disposed channelsextend into and out of the page through a depth portion of die 120,including an entire portion of the depth of the die or substantially theentire portion of the depth of the die (e.g., 70 percent, 80 percent or90 percent). FIG. 1 also shows the channels extending across a width ofdie 120 (defined by an x-dimension) over a portion including an entireportion or substantially the entire portion of the width dimension ofthe die (e.g., 70 percent, 80 percent, 90 percent). In one embodiment,the channels extend across an area of die 120 requiring thermalmanagement, such as an area encompassed by surface 107 of die 105. Aswill be explained later, a portion of the channels, including an activeportion, alternately bring a cooling fluid toward die 105 and takeheated fluid away from die 105 for the purpose of heat transfer.

In one embodiment, backside 107 of die 105 is connected to die 120through a thermally conductive material. In one embodiment, each ofbackside 107 of die 105 and a mating side of die 120 have a thermallyconductive material such as a copper material (e.g., a copper layerand/or copper nanorods) and the dice are connected through a conductivematerial bond (e.g., a copper-copper bond). In one embodiment, each dieincludes a barrier layer on which the thermally conductive material(e.g., copper) is disposed. Representatively, die 105 and die 120 eachhave a thickness on the order of 600 microns (μm) to 900 μm.

An inset of FIG. 1 shows a magnified view of a portion of interface 140of die 105 and die 120. In this embodiment, interface includes barrierlayer 1401 formed on surface 107 of die 105. Barrier layer 1401 is, forexample, a titanium material having a representative thickness on theorder of about 100 nanometers (nm). Disposed directly on barrier layer1401 is adhesive layer 1402 of, for example, a nitride material (e.g.,titanium nitride). In one embodiment, adhesive layer 1402 has athickness on the order of 250 nm. Disposed on adhesive layer 1402 is athermally conductive material such as copper (e.g., a copper layerand/or nanorods). A mating side of die 120 similarly includes barrierlayer 1406 disposed on a surface of die 120. Barrier layer 1406 isrepresentatively a titanium material having a thickness on the order of100 nm. Disposed directly on barrier layer 1406 is adhesive layer 1407of, for example, titanium nitride having a thickness on the order of 250nm. Disposed on adhesive layer 1407 is a thermally conductive materialsuch as copper (e.g., copper layer and/or nanorods). When die 105 anddie 120 are joined, interface 140 include thermally conductive materialinterface 1405 having a representative thickness on the order of 1 μm to3 μm. There is no conventional thermal interface material (TIM) betweendie 120 and die 105.

Overlaying die 120 in the assembly of FIG. 1 is manifold 130. Manifold130 includes inlet 142 configured to introduce a fluid into a body ofmanifold 130 and outlet 150 configured to remove fluid from a body ofmanifold 130. Disposed within a body of manifold 130 is distributorassembly 145 and collector assembly 155. Distributor assembly 145includes, in one embodiment, a number of distributors having openings influid communication with a portion of channels in die 120 including, inone embodiment, each of the channels. Similarly, collector assembly 155,in one embodiment, includes a number of collectors wherein respectiveones of the collectors are in fluid communication with a portion of thechannels in die 120, including, in one embodiment, each of the channels.The distributors that make up distributor assembly 145 are connected tothe inlet 142 and the collectors that make up collector assembly 155 areconnected to outlet 150. Accordingly, in one embodiment, a fluid (e.g.,liquid or gas) is configured to be introduced through inlet 142, to flowthrough distributor assembly 145, through a body of manifold 130 andinto channels of die 120. The fluid generally travels through thechannels to a base thereof and then out of the channels. The fluidtravelling out of the channels travels through the body of manifold 130and is collected in collector assembly 155 and removed from manifold 130through outlet 150. Manifold 130 representatively is a glass materialwith inlet 142, outlet 150, distributor assembly 145 and collectorassembly 155 formed therein. Manifold 130 has an area that covers anarea of die 120 including the channels therein. In one embodiment, anarea of manifold 130 is similar to an area of die 120. In oneembodiment, there is no conventional TIM between manifold 130 and die120.

Referring again to FIG. 1, apparatus 100, in one embodiment, alsoincludes a feedback loop to circulate cooling fluid and control itstemperature. Representatively, a level of coolant is stored in reservoir181. A suitable coolant is, for example, water. Another coolant ispropendiol. Other coolants may also be suitable. Fluid flow fromreservoir 181 to manifold 130 is driven by pump 183. An optional chiller182 may be placed downstream of reservoir 181. In one embodiment, pump183 is controlled by controller 185 which is, for example, apulse-width-modulation controller connected to an H-bridge. Downstreamof pump 183 is optional flow filter 187 and flow meter 188. Flow meter188, in one embodiment, is monitorable and controllable. Flow regimecontrol is assisted with, for example, an H-bridge, that provides thecapability to reverse the pump motor direction and applybraking/deceleration to quickly change a flow rate.Pulse-width-modulation input to a pump motor allows for precise controlof the pump speed for flow rate control. As heat flux increases from die105 and consequently the die temperature increases, a speed of pump 183can be increased to provide additional cooling. Likewise, as the dieheat flux decreases, the pump speed may be decreased to target ormaintain a constant die temperature. A temperature of the cooling fluidis measured by temperature gauge 190 that is, for example, athermocouple. Components described with respect to the representativefeedback loop may be positioned above manifold 130 or in an area awayfrom manifold 130 (e.g., on another area of printed circuit board 135).In the configuration where a representative feedback loop is positionedin an area away from manifold 130, tubing may be used to bring fluid toinlet 142 and from outlet 150.

FIG. 2A shows a top perspective view of a die including channels (e.g.,micro-channels) as part of a thermal solution. Die 220 is, in oneembodiment, a semiconductor material (e.g., single crystal silicon). Die220 includes a number of laterally disposed channels (channels 2205,2210 and 2215 identified) formed in a body of the die. Such channels maybe formed, for example, by a lithographic and etch operations or by alaser drilling operation. Representatively, each channel (e.g., channels2205, 2210 and 2215) has a width, w, on the order of 50 microns (μm) to200 μm and, in this embodiment, extends in a z-direction through thebody of die 220. Preferably, each channel has a depth, d, substantiallythrough the body of die 220 (e.g., 70 percent through the body, 80percent through the body, 90 percent through the body). In thisembodiment, the channels extend across an x-direction width of die 220.As illustrated, such channels are exposed at a top surface of die 220 asviewed. As illustrated, each channel (channels 2205, 2210 and 2215) hasa rectangular profile. It is appreciated that such profile is dependentupon the fabrication conditions and does not necessarily have to berectangular. For example, each channel may have a rounded base and/orthe sidewalls may not be parallel.

FIG. 2B shows a top perspective view of another embodiment of a dieoffering a thermal solution. In this embodiment, die 220B includeschannels disposed within a body of the die and in a z-direction throughthe body of the die. Such channels may be formed by, for example, anetch or laser drilling process and depositing a cap layer of a thermallyconductive material such as a semiconductor material on the top to closethe required openings. Access to the channels for a manifold assembly toprovide a fluid to the channels may be provided by lithographic and etchoperations to form desired openings. FIGS. 3-6 illustrate a process offorming an assembly including an active die (e.g., logic die (e.g.,central processing unit (CPU)) and a secondary die that provides athermal solution for the assembly flowchart of a method. FIG. 7 providesa flow chart of a method. Referring to FIG. 3 and FIG. 7, FIG. 3 showsdie 220 that is, for example, a secondary die or thermal solution forthe assembly. Die 220 is similar to the die shown in FIG. 2A andincludes a number of laterally disposed channels extending it in az-direction across the die. Such channels and the processes described inFIGS. 3-6 may be formed at a wafer level where die 220 is one of anumber of designated dice formed in a similar manner. Once the channelsare formed, the individual die may be singulated or such singulation mayoccur after the dice are assembled onto an active or logic die.Referring to FIG. 3, as an initial operation, channels 2205, 2210 and2215 of another channel are formed in the die by lithographic and etchoperations or by laser drilling (block 710, FIG. 7). Following thefabrication of the channels, a backside of the die (a side opposite theopen channels) is processed (block 720, FIG. 7). In one embodiment, theprocess includes forming barrier layer 221 of, for example, titaniumhaving a thickness on the order of 100 nanometers (nm) across a surfaceof the die. Following the formation of barrier layer 221, adhesive layer222 is formed. In one embodiment, adhesive layer 222 is a nitride suchas titanium nitride deposited across a surface of the die having arepresentative thickness on the order of 250 nm.

Following the formation of adhesive layer 222, a thermally conductivematerial may be formed on a die. In one embodiment, a thermallyconductive material includes copper layer 223 and copper nanorods 224.In one embodiment, copper layer 223 may be formed by an electroplatingprocess such as by seeding a surface of die 220 (an exposed surface ofadhesive layer 222) with a seed material and then plating copper layer223 across the surface. Nanorods 224 may also be plated thereon.Including nanorods 224 provides the functionality of low temperaturebonding and compensation for any y-dimension height mismatch. To platenanorods on copper layer 223, a masking layer may be initially appliedover copper layer 223 then opening may be formed in the masking layer atlocations for the nanorods. Nanorods 224 may then be plated into copperlayer 223 and then the masking layer removed. In another embodiment,only nanorods are plated by, for example, seeding an exposed surface ofadhesive layer with a seed material, masking the surface, formingopenings through the masking a nanorod locations, plating nanorods andthen removing the masking and excess seed material. In still anotherembodiment, only a copper layer (copper layer 223) is plated.

FIG. 4 shows an embodiment of a top perspective view of an embodiment ofa die including active devices and circuits process to receive the dieof FIG. 3. FIG. 4 shows die 205 that is, for example, a logic or otherdie (e.g., a memory die) including device layer 2052 of a number ofactive devices and circuitry. Die 205 may be formed according toconventional processes at a wafer level. Once formed, die 205 isprocessed to accept a secondary die such as die 220 offering thermalsolution at a singulated die or wafer level. FIG. 4 shows a backside ofdie 205 including barrier layer 206 of, for example, a titanium materialhaving a representative thickness on the order of 100 nm and barrierlayer 207 of a nitride material such as titanium nitride having arepresentative thickness on the order of 250 nm. Disposed on adhesivelayer 207 is a thermally conductive material such as copper. In thisembodiment, thermally conductive material includes layer 208 of, forexample, electroplated copper and nanorods 209 formed as described above(block 715, FIG. 7).

FIG. 5 shows the connecting of die 220 to die 205. In one embodiment,done at, for example, a wafer level, die 220 is positioned so that abackside of die 220 including the thermally conductive material (copperlayer 223 and/or nanorods 224), in this embodiment, is facing a similarthermally conductive material on die 205. The two dice are aligned andthermally bonded together (block 725, FIG. 7). FIG. 6 shows the assemblyincluding the connected die 205 and die 220. In this embodiment, theconnection forms interface 240 of the thermally conductive material onthe surface of each die. If processed at a wafer level for each die,following the connection (e.g., thermal bonding) of the dice, the twowafers may be singulated to produce a separate composite structure orassembly as shown in FIG. 6.

FIG. 8 shows another embodiment of an assembly including a thermalsolution of a die having channels (e.g., micro-channels or micro-jets)formed therein for a fluid cooling solution. Referring to FIG. 8,assembly 400 includes active die 405 that is, for example, a logic diesuch as CPU. Overlaying die 405 is die 420 that includes a thermalsolution of, for example, channels formed therein. Die 405 and die 420may be connected (connected on a backside or non-device side of logicdie 405) by interface 440 of a thermally conductive material such ascopper as described above. A device side of die 405 is connected tosubstrate 415 such as a package substrate or printed circuit board by,for example, solder connections (e.g., a ball grid array). Die 420includes, in one embodiment, a number of a laterally disposed channelsas described above. In one embodiment, the channels are exposed on asurface of the die (similar to FIG. 2A). Disposed on die 420, in thisembodiment, is manifold 430. Manifold 430 includes therein a distributorassembly and a collector assembly. Distributor assembly 445 includes, inone embodiment, a number of distributors having openings in fluidcommunication with a portion of the channels in die 420 (e.g., all ofthe channels) and collector assembly 455, in one embodiment, includes anumber of collectors wherein the respective ones of the collectors arealso in fluid communication with a portion of the channels in die 420.The distributors that make up distributor assembly 445 are connected toinlet 440 and collectors that make up collector assembly 455 areconnected to outlet 450A or outlet 450B.

In this embodiment, connected to the assembly of die 420 and die 405 issupport 475. In one embodiment, support 475 is connected to the assemblythrough substrate 415 by support screws 480. Support 475, in oneembodiment, has an area dimension larger than the individual die (e.g.,30 percent larger, 50 percent larger) so as to cover a surface ofmanifold 430 and die 420 and die 405 between the support and substrate415. Disposed in support 475 is inlet pipe 485 (e.g., plastic tubing)and outlet pipe 490A and outlet pipe 490B. The inlet pipes and outletpipes through support 475 are aligned with inlet 440 and outlets 450Aand 450B of manifold 430, respectively. The interface of the inlet andoutlet pipes with the inlet and the outlets of the manifold are sealedby, for example, O-rings 418. In this embodiment, fluid, such as water,is introduced into inlet 485. The fluid flows through distributorassembly 445 in manifold 430 and into channels of die 420. The fluidthen flows through corrector assembly 455 in manifold 430 and is removedthrough outlet 450A or outlet 450B into outlet pipe 490A and outlet pipe490B, respectively. The assembly of FIG. 8 may include a feedback loopsuch as described above with reference to FIG. 1 to circulate coolingfluid and control as temperature.

FIG. 9 shows a cross-sectional side view of another embodiment of anassembly offering a thermal solution. Referring to FIG. 9, the figureshows die 505 that is, for example, logic die or CPU having a devicelayer wherein the device layer is connected to substrate 515 such as apackage substrate or printed circuit board. Disposed on a backside ofdie 505 is die 520 that provides a thermal solution in the form of anumber of channels formed as described above. Die 505 and die 520 areconnected to one another through interface 540 of a thermally conductivematerial such as copper. Disposed on a surface of die 520 (a top surfaceas viewed) is manifold 530 of, for example, a glass material. Disposedwithin manifold 530 is distributor assembly 545 including, in oneembodiment, a number of distributors having an openings in fluidcommunication with a portion of the channels in die 520 (e.g., all ofthe channels in die 520). Also disposed in manifold 530 is collectorassembly 555 including a number of collectors, wherein the respectiveones of the collectors are in fluid communication with a portion of thechannels in die 520. Distributors that make up distributor assembly 545are connected to inlet 540 and collectors that make up collectorassembly 555 are connected to outlet 550. Disposed over manifold 530, inthis embodiment, is integrated heat spreader (IHS) of, for example, athermally conductive material which is a metal. In one embodiment, IHS575 completely surrounds the assembly of die 505, die 520 and manifold530. In this manner, the assembly is encased within IHS 575. In oneembodiment, there is no TIM between IHS 575 and manifold 530 or betweenmanifold 530 and die 520. As viewed, inlet 540 and outlet 550 extendfrom manifold 530 through IHS 575. Accordingly, a fluid may beintroduced through inlet 540 at a surface of IHS 575 (a top surface, asviewed) and through manifold 530 and die 520 and return to outlet 550through IHS 575. The assembly of FIG. 9 may include a feedback loop suchas described above with reference to FIG. 1 to circulate cooling fluidand control as temperature.

FIG. 10 shows a cross-sectional side view of another embodiment of anassembly including a multi-chip package (MCP). In this embodiment, anMCP is illustrated including three different die assemblies connected tothe same package. FIG. 10 shows a first assembly including die 505A thatis, for example, an active die connected to die 520A that has a thermalsolution of, for example, micro-channels or micro-jets as describedabove; die 505B that has an active die connected to die 520B thatincludes a thermal solution; and die 505C connected to die 520C thatincludes a thermal solution. Dice 505A, 505B and 505C may each be alogic die (e.g., a processor) or other functional die (e.g., a memorydie). Each of a device side of die 505A, die 505B and die 505C isconnected to substrate 515 (e.g., a package substrate) through, forexample, solder connections. Overlaying each of die 520A, die 520B anddie 520C is a manifold. FIG. 10 shows manifold 530A on die 520A,manifold 530B on die 520B, and manifold 530C on die 520C. Each manifoldrepresentatively includes a distributor assembly and a collectorassembly as described above.

Overlaying the three dice in the multi-chip package assembly is IHS 575of, for example, a thermally conductive material. In this embodiment,IHS 575 completely surrounds or encompasses the three dice. In oneembodiment, there is no TIM between the manifolds and IHS 575 or betweenthe manifolds and dice 520A-520C, respectively.

FIG. 10 shows inlet 540 connected to manifold 530A. Inlet 540 isconfigured to deliver a fluid such as water to manifold 530A and thedistributor assembly therein. The fluid flows through the micro-channelsor micro-jets of die 520A and into a collector assembly of manifold530A. From the collector assembly, the fluid moves through outlet 545A.In this embodiment, outlet 545A also serves as an inlet to the assemblyincluding die 505B and die 520B. Outlet 545A is connected as an inlet tomanifold 530B and fluid flows into manifold 530B, through thedistributor assembly therein and into the micro-channels or micro-jetsof die 520B and is collected through the collector assembly therein. Thecollector assembly in manifold 530B transfers the fluid to outlet 545B.Outlet 545B, in this embodiment, also serves as the inlet to theassembly including die 505C and die 520C. Outlet 545B delivers fluid tomanifold 530C. The fluid travels through the distributor assemblytherein and is collected through the collector assembly and releasethrough outlet 550. Outlet 550 is disposed through IHS 575.

FIG. 11 illustrates computing device 600 in accordance with oneimplementation. Computing device 600 houses board 602. Board 602 mayinclude a number of components, including but not limited to processor604 and at least one communication chip 606. Processor 604 is physicallyand electrically coupled to board 602. In some implementations at leastone communication chip 606 is also physically and electrically coupledto board 602. In further implementations, communication chip 606 is partof processor 604. Depending on its applications, computing device 600may include other components that may or may not be physically andelectrically coupled to board 602. These other components include, butare not limited to, volatile memory (e.g., DRAM), non-volatile memory(e.g., ROM), flash memory, a graphics processor, a digital signalprocessor, a crypto processor, a chipset, an antenna, a display, atouchscreen display, a touchscreen controller, a battery, an audiocodec, a video codec, a power amplifier, a global positioning system(GPS) device, a compass, an accelerometer, a gyroscope, a speaker, acamera, and a mass storage device (such as hard disk drive, compact disk(CD), digital versatile disk (DVD), and so forth).

Communication chip 606 enables wireless communications for the transferof data to and from computing device 600. The term “wireless” and itsderivatives may be used to describe circuits, devices, systems, methods,techniques, communications channels, etc., that may communicate datathrough the use of modulated electromagnetic radiation through anon-solid medium. The term does not imply that the associated devices donot contain any wires, although in some embodiments they might not.Communication chip 606 may implement any of a number of wirelessstandards or protocols, including but not limited to Wi-Fi (IEEE 802.11family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term evolution(LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT,Bluetooth, derivatives thereof, as well as any other wireless protocolsthat are designated as 3G, 4G, 5G, and beyond. Computing device 600 mayinclude a plurality of communication chips 606. For instance, firstcommunication chip 606 may be dedicated to shorter range wirelesscommunications such as Wi-Fi and Bluetooth and second communication chip606 may be dedicated to longer range wireless communications such asGPS, EDGE, GPRS, CDMA, WiMAX, LTE, Ev-DO, and others.

Processor 604 of computing device 600 includes an integrated circuit diepackaged within processor 604. In some implementations, the integratedcircuit die of the processor may include or be part of a thermalsolution such as described above. The term “processor” may refer to anydevice or portion of a device that processes electronic data fromregisters and/or memory to transform that electronic data into otherelectronic data that may be stored in registers and/or memory.

Communication chip 606 also includes an integrated circuit die packagedwithin communication chip 606. In accordance with anotherimplementation, the integrated circuit die of the communication chip mayinclude or be part of a thermal solution such as described above.

In further implementations, another component housed within computingdevice 600 may contain an integrated circuit die may include or be partof a thermal solution such as described above.

In various implementations, computing device 600 may be a laptop, anetbook, a notebook, an ultrabook, a smartphone, a tablet, a personaldigital assistant (PDA), an ultra mobile PC, a mobile phone, a desktopcomputer, a server, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a digital camera, a portable music player,or a digital video recorder. In further implementations, computingdevice 600 may be any other electronic device that processes data.

In the description above, for the purposes of explanation, numerousspecific details have been set forth in order to provide a thoroughunderstanding of the embodiments. It will be apparent however, to oneskilled in the art, that one or more other embodiments may be practicedwithout some of these specific details. The particular embodimentsdescribed are not provided to limit the invention but to illustrate it.The scope of the invention is not to be determined by the specificexamples provided above but only by the claims below. In otherinstances, well-known structures, devices, and operations have beenshown in block diagram form or without detail in order to avoidobscuring the understanding of the description. Where consideredappropriate, reference numerals or terminal portions of referencenumerals have been repeated among the figures to indicate correspondingor analogous elements, which may optionally have similarcharacteristics.

It should also be appreciated that reference throughout thisspecification to “one embodiment”, “an embodiment”, “one or moreembodiments”, or “different embodiments”, for example, means that aparticular feature may be included in the practice of the invention.Similarly, it should be appreciated that in the description variousfeatures are sometimes grouped together in a single embodiment, figure,or description thereof for the purpose of streamlining the disclosureand aiding in the understanding of various inventive aspects. Thismethod of disclosure, however, is not to be interpreted as reflecting anintention that the invention requires more features than are expresslyrecited in each claim. Rather, as the following claims reflect,inventive aspects may lie in less than all features of a singledisclosed embodiment. Thus, the claims following the DetailedDescription are hereby expressly incorporated into this DetailedDescription, with each claim standing on its own as a separateembodiment of the invention.

What is claimed is:
 1. An integrated circuit assembly comprising: a first die comprising a device side and a backside opposite the device side; and a second die comprising a plurality of fluidly accessible channels therein, wherein the second die is coupled to a backside of the first die.
 2. The integrated circuit assembly of claim 1, further comprising a copper material disposed between the first die and the second die.
 3. The integrated circuit assembly of claim 2, wherein the copper material comprises at least one of a copper layer and a plurality of copper nanorods.
 4. The integrated circuit assembly of claim 2, wherein the copper material is disposed between at least one of a barrier layer and an adhesive layer on each of a first die side and a second die side of the copper material.
 5. The integrated circuit assembly of claim 1, further comprising a lid disposed on the second die, the lid comprising an area dimension that covers an area comprising the channels.
 6. The integrated circuit assembly of claim 5, wherein the lid comprises a fluid inlet and a fluid outlet.
 7. The integrated circuit assembly of claim 1, wherein a material of the first die and a material of the second die are each a semiconductor material.
 8. An integrated circuit assembly comprising: at least one package comprising: a first die comprising a device side and a backside opposite the device side; a second die coupled to the backside of the first die, the second die comprising a plurality of channels therein and a fluid inlet operable to deliver a fluid to the plurality of channels and a fluid outlet; and a package substrate coupled to the device side of the die.
 9. The integrated circuit assembly of claim 8, further comprising a copper material disposed between the first die and the second die.
 10. The integrated circuit assembly of claim 9, wherein the copper material comprises at least one of a copper layer and a plurality of copper nanorods.
 11. The integrated circuit assembly of claim 8, wherein the at least one package further comprises a lid disposed on the second die, the lid comprising an area dimension that covers an area comprising the channels.
 12. The integrated circuit assembly of claim 11, wherein the lid comprises the fluid inlet and the fluid outlet.
 13. The integrated circuit assembly of claim 8, further comprising a support disposed on the at least one package such that the first die and the second die are disposed between the package substrate and the support.
 14. The integrated circuit assembly of claim 8, further comprising an integrated heat spreader coupled to the package substrate and encapsulating a portion of the at least one package, the integrated heat spreader comprising an inlet port coupled to the fluid inlet and an outlet port coupled to the fluid outlet.
 15. The integrated circuit assembly of claim 14, wherein the at least one package comprises a first package and a second package.
 16. The integrated circuit assembly of claim 15, wherein the inlet port of the integrated heat spreader is coupled to the fluid inlet of the first package and the fluid outlet of the first package is coupled to fluid inlet of the second package and the outlet port of the integrated heat spreader is coupled to the fluid outlet of the second package.
 17. A method of fabricating an integrated circuit assembly comprising: coupling a first die to a second die, wherein the first die comprises a device side and an opposite backside, wherein the device side comprises a plurality of integrated circuits and wherein the second die comprises a plurality of fluidly accessible channels therein.
 18. The method of claim 17, wherein prior to coupling the first die to the second die, the method comprises coupling a copper material to at least one the backside of the first die and the second die such that the copper material is between the first die and the second die following the coupling of the first die and the second die.
 19. The method of claim 18, wherein prior to coupling the first die to the second die, the method comprises coupling a copper material to each of the backside of the first die and the second die such that the copper material coupled to each of the first die and the second die is between the first die and the second die following the coupling of the first die and the second die.
 20. The method of claim 17, further comprising coupling a fluid inlet and a fluid outlet to the channels. 